The Adsorption of Tetrachloroethylene and Trichlorofluoromethane on Anhydrous Nickel Sulfate

Several anomalous features of the adsorption isotherms obtained with tetrachloroethylene and trichlorofluoromethane on anhydrous nickel sulfate at 20.0, 5.8, and −7.5 °C, have been explained using a parallel plate pore model. Application of the Kelvin equation to the system indicates that adsorption hysteresis is due primarily to contact angle hysteresis, and that the thickness of the adsorbed layer that does not participate in meniscus formation is independent of relative pressure. Heats of immersion calculated from the estimated contact angles, and from heats of adsorption, have provided some support for the model.